JPH05106421A - Intake and exhaust noise reducing device for internal combustion engine - Google Patents

Abstract

PURPOSE:To provide a device to reduce the intake and the exhaust noise effectively. CONSTITUTION:While a pressure differential generating means to generate a pressure differential in a low pressure passage 14 and a high pressure passage 15 is provided, a valve means 16 to communicate an intake pipe 2 and an exhaust pipe 3 to the lower pressure passage 14 and to the high pressure passage 15 alternatively is provided. And the valve means 16 is composed to drive to open and close synchronously to one rotation of the engine, so as to offset the pressure pulsations generated in the intake pipe 2 and the exhaust pipe 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake / exhaust noise reduction system for an internal combustion engine.

[0002]

2. Description of the Related Art In automobiles and the like, as the quietness of the engine body is improved. There is an increasing demand for reduction of intake and exhaust noise.

As a measure against this, for example, the actual exploitation Sho 63-11
In Japanese Patent No. 379, a microphone and a speaker are attached in the middle of an intake pipe, and a sound pressure signal detected by the microphone and a phase signal from a crank angle sensor are input to a control unit, where signal processing is performed to obtain an intake sound. The amplitude and phase of the sound that is the opposite phase to
It has been proposed to reduce the intake / exhaust sound by generating sound waves having the same phase as the intake / exhaust sound from the speaker and having an opposite phase.

Since the intake sound is mainly perceived as a pressure wave caused by the pressure pulsation associated with the opening and closing of the intake valve, if pressure waves of the same frequency and opposite phases can be applied so as to cancel this pressure wave, both of them can be applied. It is known that the waves of the waves interfere with each other and cancel each other, and the amplitude of the waves, that is, the sound pressure is weakened.

[0005]

In the case of an automobile engine,
The problem of intake noise or exhaust noise is in the low frequency range of 100 Hz or less, and particularly when resonance occurs in this low frequency range, vibration may be amplified and an uncomfortable muffled sound may be generated in the vehicle interior. ..

However, in such a conventional device, since the speaker produces the same sound pressure as the intake and exhaust sounds, the sound pressure equivalent to the resonance sound generated in the low frequency range of 100 Hz or less in the intake pipe. Is difficult to generate from the speaker, which leads to an increase in the size of the speaker, an increase in weight and deterioration of mountability in a vehicle, and also an increase in power consumption for driving the speaker.

It is an object of the present invention to provide an apparatus which effectively reduces the intake / exhaust noise by paying attention to the above points.

[0008]

According to the present invention, a pressure difference generating means for creating a pressure difference between a low pressure passage and a high pressure passage is provided, and a low pressure passage and a high pressure passage are alternately provided to at least one of an intake pipe and an exhaust pipe. The communicating valve means is provided and the valve means is opened and closed in synchronization with the engine rotation so as to cancel the pressure pulsation generated in the intake pipe or the exhaust pipe.

[0009]

[Function] Although the intake / exhaust valve is opened / closed, a pressure pulsation in synchronization with the engine rotation is generated in the intake / exhaust pipe. Is awakened. By appropriately setting the opening / closing cycle of the valve means and the volume of the intake / exhaust pipe so that the phases of both pressure pulsations are reversed, both pressure pulsations interfere and cancel each other out, resulting in a pressure wave generated in the intake / exhaust pipe. That is, the sound pressure of the intake and exhaust sounds can be weakened.

By appropriately setting the pressure difference between the low pressure passage and the high pressure passage formed by the pressure difference generating means, it is possible to easily generate a pressure pulsation having a large amplitude in the low frequency range and amplify the secondary vibration of the engine. The pressure pulsation of the intake / exhaust that is generated can be effectively cancelled, and the muffled noise in the vehicle interior can be reduced and the noise to the outside of the vehicle can be effectively reduced.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 2, an intake pipe 2 and an exhaust pipe 3 are connected to the 4-cylinder engine 1, respectively. The intake pipe 2 includes an intake manifold 4, which is connected to each cylinder through an intake port, a duct 7, a throttle chamber 6 in which a throttle valve 5 for adjusting the intake amount is installed, a duct 8, an air cleaner 9 which takes in outside air, and the like. ..

As shown in FIG. 1, a vane pump 10 that is driven in synchronization with engine rotation is provided as a pressure difference generating means. In the vane pump 10, a cylindrical main rotor 11 and an auxiliary rotor 12 are rotatably interposed in a housing 13 of the vane pump 10. The main rotor 11 has an outer peripheral surface 11
The auxiliary rotor 12 has a concave portion 12B on its outer peripheral surface 12A, while the vane 11B protrudes from A in the radial direction. The main rotor 11 and the auxiliary rotor 12 are arranged close to each other so that there is almost no gap between them, and the vane 11B
And the recess 12B are engaged with each other and rotate in opposite directions as indicated by an arrow. In the section in which the vane 11B is engaged with the recess 12B, the high pressure passage 15 and the low pressure passage 14 are in communication with each other and have the same pressure.

The housing 13 has a cylindrical wall portion 13A which is concentric with the main rotor 11, and the cylindrical wall portion 13A and the vane 11B.
There is almost no gap between them, and the rotation of the main rotor 11 expands the volume on the low pressure passage 14 side defined by the vane 11B in the housing 13, and the high pressure passage 15
The side volume is reduced, the pressure in the low pressure passage 14 is decreased, and the pressure in the high pressure passage 15 is increased.

The rotating shaft 11C of the main rotor 11 and the rotating shaft 12C of the auxiliary rotor 12 rotate in opposite directions and rotate at the same rotation speed via a gear (not shown), and rotate from the crankshaft via a timing belt, a pulley and the like. Power is transmitted. Further, motors for respectively driving the rotating shaft 11C of the main rotor 11 and the rotating shaft 12C of the auxiliary rotor 12 may be provided so as to be driven in synchronization with the engine rotation via the control device.

A rotary valve 16 is provided as a valve means for alternately connecting the low pressure passage 14 and the high pressure passage 15 of the vane pump 10 to the intake pipe 2. Intake pipe 2 at one end
A waveguide 17 is provided to be connected to the rotary valve 16. The other end of the waveguide 12 and a branch portion of the low pressure passage 14 and the high pressure passage 15 of the vane pump 10 are provided with a rotary valve 16.

The cylindrical rotary valve 16 has a port 16A penetrating its inside, and its rotation causes the port 1
The low pressure passage 14 and the high pressure passage 15 are alternately communicated with the intake pipe 2 via 6A.

Rotational force from the crankshaft is transmitted to the rotary shaft 16B of the rotary valve 16 via a timing belt, a pulley and the like. In addition, the rotary valve 1
A motor for driving the rotary shaft 16B of No. 6 may be provided to drive the rotary shaft 16B in synchronization with the engine rotation via the control device.

Since the opening / closing timing of the intake valve that causes the pressure pulsation in the intake pipe 2 is synchronized with the rotation of the crankshaft, the frequency of the pressure pulsation in the intake pipe 2 is the engine speed Ne.
Proportional to.

Therefore, by setting the rotations of the main rotor 11 and the rotary valve 16 so as to be synchronized with the engine rotation speed Ne at an appropriate rotation speed ratio, the frequency of the pressure pulsation generated in the intake pipe 2 is α Hz. Sometimes, the number of revolutions per second of the main rotor 11 is α, and
The number of rotations of the rotary valve 16 per second is α / 2. That is, each time the pressure of the intake pipe 2 vibrates once, the main rotor 11 makes one revolution, and the port 16A of the rotary valve 16 connects the low pressure passage 14 and the high pressure passage 15 of the vane pump 10 once. ..

As a result, the pressure pulsation is generated in the waveguide 16 once for each half rotation of the rotary valve 16. By arbitrarily setting the conduit length and volume of the waveguide 16, the phase of the pressure pulsation incident on the intake pipe 2 from the waveguide 16 becomes the pressure pulsation generated in the intake pipe 2 with the opening and closing of the intake valve. Reverse it. As a result, both pressure pulsations interfere with each other and cancel each other out, and the amplitude of the pressure wave generated in the intake pipe 2, that is, the sound pressure of the intake sound is weakened.

As described above, by operating the vane pump 10 and the rotary valve 16, it is possible to easily generate a pressure pulsation having a large amplitude in a low frequency range as compared with the conventional device having a speaker, and to amplify the secondary vibration of the engine. It is possible to effectively cancel the pressure pulsation of the intake air, reduce the muffled sound in the vehicle interior, and effectively reduce the noise outside the vehicle.

In another embodiment shown in FIG. 3, a rotary valve 26 is formed in a C-shaped cross section, and an opening 13B is opened in the housing 13 below the rotary valve 16 and the opening 13B is formed in the opening 13B. One end of the waveguide 17 is connected.
The waveguide 17 is connected to the low-pressure passage 14 and the high-pressure passage 15 while the rotary valve 26 makes one rotation.

Rotational force from the crankshaft is transmitted to the rotary shaft 26B of the rotary valve 26 via a timing belt, a pulley and the like. By setting the rotational speeds of the main rotor 11 and the rotary valve 16 at appropriate ratios with respect to the engine rotational speed Ne, when the frequency of the pressure pulsation generated in the intake pipe 2 is αHz, the main rotor 11 per second And the rotary valve 2
The rotation number per second of 6 is α. As a result, the main rotor 11 rotates once each time the pressure in the intake pipe 2 vibrates once, and the waveguide 17 is communicated with the low pressure passage 14 and the high pressure passage 15 once via the rotary valve 26. The pressure pulsation of the intake pipe 2 is canceled.

In this case, the rotary valve 26 can secure a relatively large opening area, and the passage cross-sectional area between the waveguide 17 and the low pressure passage 14 and the high pressure passage 15 is not greatly reduced. The pressure pulsation can be easily set.

Next, another embodiment shown in FIG. 5 is provided with a roots-type blower 30 which is driven in synchronism with the rotation of the engine as a pressure difference generating means, and its housing 33 is in synchronism with the engine. A pair of rotating eyebrows type rotors 31, 32
Is provided.

By rotating the rotors 31 and 32 in reverse as shown by the arrows while engaging with each other, the volume on the low pressure passage 14 side defined by the housing 33 is increased, and the volume on the high pressure passage 15 side is defined. Is reduced, the pressure in the low pressure passage 14 is decreased, and the pressure in the high pressure passage 15 is increased.

Rotating shafts 31C, 32 of the rotors 31, 32
C rotates counterclockwise and rotates at the same rotational speed via a gear (not shown), and the rotational force from the crankshaft is transmitted via a timing belt, a pulley, and the like.

Also in this embodiment, a rotary valve 16 is provided as a valve means for alternately connecting the low pressure passage 14 and the high pressure passage 15 of the roots type rotor 30 to the intake pipe 2.
When the frequency of the pressure pulsation generated in the intake pipe 2 is αHz,
The number of revolutions per second of each rotor 31, 32 is α / 2, and the number of revolutions per second of the rotary valve 16 is α / 2. That is, each time the pressure of the intake pipe 2 vibrates once, the rotors 31 and 32 make a half rotation, and the port 16A of the rotary valve 16 causes the low-pressure passage 14 of the vane pump 10 to rotate.
The high pressure passage 15 and the high pressure passage 15 communicate with each other once.

In the above embodiment, the pressure wave generator is connected to the intake pipe in order to reduce the intake noise.
In order to reduce the exhaust noise, the exhaust pipe 3 is provided with the vane pump 10 or blower 30 of each of the above-described embodiments, and the rotary valve 1
It may be connected via 6 or 26. Exhaust sound is mainly perceived as a pressure wave due to pressure pulsation associated with opening and closing of an exhaust valve, so if a pressure wave with the same frequency and opposite phase can be added to cancel this pressure wave, both waves will They interfere with each other and cancel each other out, reducing the exhaust noise.

[0031]

As described above, according to the present invention, in the intake / exhaust noise reducing apparatus for the internal combustion engine, the pressure difference generating means for creating a pressure difference between the low pressure passage and the high pressure passage is provided, and at least one of the intake pipe and the exhaust pipe is provided. A valve means for alternately connecting the low pressure passage and the high pressure passage is provided, and the valve means is opened and closed in synchronization with the engine rotation so as to cancel the pressure pulsation generated in the intake pipe or the exhaust pipe. The pressure pulsation having a large amplitude can be easily generated in the low frequency range as compared with the conventional device including the above, and the muffled noise in the vehicle interior and the vehicle noise can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is likewise an overall configuration diagram.

FIG. 3 is a sectional view showing another embodiment.

FIG. 4 is a sectional view taken along line XX of FIG.

FIG. 5 is a sectional view showing still another embodiment.

[Explanation of symbols]

 1 Engine 2 Intake Pipe 3 Exhaust Pipe 10 Vane Pump 14 Low Pressure Passage 15 High Pressure Passage 16 Rotary Valve

Claims (1)

[Claims] 1. A pressure difference generating means for creating a pressure difference between the low pressure passage and the high pressure passage, and valve means for alternately connecting the low pressure passage and the high pressure passage to at least one of the intake pipe and the exhaust pipe are provided. An intake / exhaust noise reduction system for an internal combustion engine, characterized in that the valve means is opened / closed in synchronism with engine rotation so as to cancel out pressure pulsation generated in a pipe or an exhaust pipe.